Towards the thermal reactivity and behavior of co-agglomerated crystals of DATB and TATB with attractive nitramines

Abstract

The thermolysis of the co-agglomerates (CACs) of the attractive nitramines RDX, BCHMX, HMX and CL-20 with 1,3-diamino-2,4,6-trinitrobenzene (DATB) and 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) was studied by means of differential thermal analysis (DTA) and differential scanning calorimetry (DSC), using the Kissinger method for output evaluation. The insertion of both DATB and TATB molecules into nitramine crystal lattices markedly increased the thermal sensitivity of the resulting CACs to overheating. Depression in melting points was detected in all CACs and, with the exception of RDX CACs, also in the exothermic peaks. The RDX CACs differ from the other studied CACs by their decomposition in the liquid state. The activation energies (Ea), obtained correlate with asymmetric N-O stretching vibrations, confirming the important influence of ‒N‒O⋅⋅⋅⋅H‒N= interactions in CACs; a similar correlation with asymmetric NO2 stretching confirms the interactions of DATB and TATB molecules with nitramine molecules through van der Waals forces. The insertion of DATB or TATB into the crystal lattice of HMX or CL20 changes their polymorphic modification from β- to δ- and in the latter case from εto β- modifications in the corresponding CACs. The correlations of the Ea values with the square of detonation velocity as a representative of performance and with the heat of combustion as a representative of the energy content are consistent with already previously described relationships of this type, including exceptions for pure nitramines.